Local variation of element concentrations in a NPLE based austenite to ferrite phase transformation model

Abstract

In this work we present an austenite to ferrite phase transformation model based on local equilibrium with negligible partitioning for steels for which manganese is the thermodynamically dominant substitutional alloying element. By introducing some simplifications, the diffusion controlled transformation can be calculated with comparatively low computational costs. Besides geometrical effects and nucleation, local variation of element concentration is also taken into account, which improves the prediction quality. Segregation effects are estimated by electron microprobe analyzer measurements and compared to thermodynamic calculations. The model is first tested on four model alloys, then on a large number of alloys with a composition close to industrial steel grades.